German Patent No. 36 04 216 describes discloses a rollover sensor consisting of a fluid-filled space in which a body, suspended in the manner of a pendulum, is located as a seismic mass. By means of an electrical analysis circuit, changes in the position of the pendulum, which can deflect in any direction, yield information as to whether or not the vehicle is rolling over. This rollover sensor based on the pendulum principle has the disadvantage that it reacts too slowly to vehicle movements, so that a rollover might possibly be signaled too late to activate the occupant protection mechanisms.
European Patent No. 430 813 describes a safety system for a vehicle which extends a rollover bar in the event of a vehicle rollover. In order to be able to sense a rollover event, the system possesses acceleration sensors to measure the accelerations of the vehicle in the directions of its yaw axis, its roll axis, and its pitch axis, and it has at least one rotation rate sensor which measures the angular velocity of the vehicle (FZ) with respect to its roll axis.